Tiers Monde

Pragmatics is the study of how language is used in communication, concerned with appropriateness, both with regard to what is said in a particular context and how it is said. 

Learners have to learn when it is appropriate to perform a particular language function and also how to encode it. 

Thomas(1983) distinguishes

Sociopragmatic failure:when learners produce socially inappropriate behaviour

Pragmalinguistic failure: when learners do not express themselves in a linguistically appropriate manner.